Well Ive severly neglected my 75 gal saltwater tank this past year. I had a bunch of freshwater tanks and this one saltwater. But I was working a lot and really wasnt taking care of my tanks. I sold off most of my freshwater tanks except my bigger ones (220g, 110g and 55g) and now today I decided to do something with the saltwater.

For the past year Ive only added water to my tank. 5 gal, once a week or so. Havent done a single water change. I have a Oddysea T5 ho fixture running a daylight bulb and a 10000k Acticic bulb thats on for 2 hours a day. One side of the tank glass was covered in thick green hair algae, brown algae and some purple/brownish algae. Substrate was pretty nasty with broken down waste and whatnot. Salinity was only 1.019, Nitrate was at a solid 160ppm although nitrite and ammonia both appear to be 0 ppm. I have a couple pieces of live rock with nice purple algae on them but most of it is just nasty brown/green. Theres also a couple big blobs of clear/white slime on a couple rocks. I removed the fish (2 clown fish) and pulled most of the live rock so i can clean the tank out and ad an extra 20lb of crushed coral to fill in the low spots (didnt put enough in when I set the tank up. I cant decide if I should put all the rock back in or keep the bad looking rocks out and clean/dry them out. Will new, better water conditions regular water changes kill off the bad algae over time? I think it mainly grew because of the tank being next to a window so I was going to either paint that side glass like I did the back of the tank or block it from the sun another way. Are there any fish or inverts thatll eat the bad algae?

Im also considering adding a protein skimmer, not sure if thats completely necessary or not, but if it'll help Im willing to buy one. Right now we just have the 2 clowfish and some small crabs. But once I get the tank running like it should again I plan on getting a couple more fish

If I were to take on a tank like that I would probably start over. If you want to salvage what you have, then get a toothbrush and start scrubbing the rock. Take a razor and scrape the sides. Suction all of the bad stuff out. I'd do a 50% waterchange and and then 20% every other week. If youre not using RODI water, then youll continue to have algee problems or worse. You'll probably have those growths for a little while, but they should taper down as you gradually cleanse your tank. A protain skimmer will help, but if you're not doing your water changes it means little to your overall problems.

I vacuumed the substrate last night draining probably 1/3 of the water and added 20lbs of crushed coral. scraped all the glass off and filled the tank back up and let it clear up over night. This morning I checked the nitrate and it was still at 80ppm. So I just drained about 80% of the water down and refilled it back up and am going to let it sit and settle now while I decide what to do with the rocks. A couple of the bigger rocks are still decent looking and Id like to just put them back in the tank. Is there any real danger to doing that? if theres some green/brown algae on a rock that I put in there is it going to spread all over the tank again?

Looking at the rocks there really doesnt seem to be any life in them other than the algae. A couple of the rocks have a bunch spots of clear slime with what looks like little white eggs in them. 1 rock has a bunch of tiny hard white tubes growing on it that have what looks like a feather duster that sticks out of the end and sucks in if something goes near it. But theres no bugs or anything that moves on them. Most of the rock is just colored green, brown, purple/marroon No snails in the tank either

If most of the bad will go away with proper lighting, water changes etc. Ill put it back in the tank. But if its more than likely going to cause problems ill just start over with it.

Fishkeeper15379 wrote:I vacuumed the substrate last night draining probably 1/3 of the water and added 20lbs of crushed coral. scraped all the glass off and filled the tank back up and let it clear up over night. This morning I checked the nitrate and it was still at 80ppm. So I just drained about 80% of the water down and refilled it back up and am going to let it sit and settle now while I decide what to do with the rocks. A couple of the bigger rocks are still decent looking and Id like to just put them back in the tank. Is there any real danger to doing that? if theres some green/brown algae on a rock that I put in there is it going to spread all over the tank again?

Looking at the rocks there really doesnt seem to be any life in them other than the algae. A couple of the rocks have a bunch spots of clear slime with what looks like little white eggs in them. 1 rock has a bunch of tiny hard white tubes growing on it that have what looks like a feather duster that sticks out of the end and sucks in if something goes near it. But theres no bugs or anything that moves on them. Most of the rock is just colored green, brown, purple/marroon No snails in the tank either

If most of the bad will go away with proper lighting, water changes etc. Ill put it back in the tank. But if its more than likely going to cause problems ill just start over with it.

It's my understanding that crushed coral doesn't have the same benefits as live sand. So adding more doesn't provide any filtration or enrichment for your water. If your concerned about the quality of your live rock, then you can always re-seed it. Just get a cup of sand from someones bed or rubble rock from the LFS. Id get your water perimeters straight before doing that though.

I'm curious as to whats on your rock. Post a picture and we'll let you know. Good Luck! Glad to see you're getting it in order.

I only added the crushed coral because I had a bag of it that Ive been meaning to ad for a good year now, the substrate was a little thin. Ill try to take some pics tomorrow if I can see what what I described. All the decent looking rock is back in the tank now.